1. Field of the Invention
The invention relates to a process for forming housings for electronic modules, and to electronic modules that are hermetically encapsulated in this way, in particular sensors, integrated circuits and optoelectronic components.
2. Description of Related Art
To encapsulate integrated circuits and optoelectronic components, it is known to use an organic adhesive layer to bond a thin plate of glass onto the module and thereby to cover and protect the sensitive semiconductor structures. This design has the drawback that over the course of time water can diffuse into the organic adhesive layer and can then reach and damage the semiconductor structures. Furthermore, the adhesive layers may age as a result of UV irradiation, which is damaging in particular to electro-optical modules.
As an alternative to organic adhesives, low-melting glass solder has also already been used as an intermediate layer which has been sprayed on, sputtered on or applied by means of screen-printing and dispenser technology. The process temperature for melting the glass-solder layer, however, is higher than T=300° C., which means that temperature-sensitive semiconductor structures cannot be encapsulated.